CN111868205A - Phase change material for heat exchange fluids/coolants - Google Patents

Abstract

The disclosure generally relates to micellar emulsions. The disclosure more particularly relates to micellar emulsions for use as thermal management fluids, methods for preparing such emulsions, and methods of using such emulsions.

Description

Phase change material for heat exchange fluids/coolants

Technical Field

The disclosure generally relates to micellar emulsions. The disclosure more particularly relates to micellar emulsions for use as thermal management fluids, methods for preparing such emulsions, and methods of using such emulsions.

Background

It is estimated that by 2035, over 1.2 million electric vehicles (i.e., vehicles that use electric power for all or a portion of their motive power, such as Battery Electric Vehicles (BEVs), Hybrid Electric Vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), etc.) will be on the road. Eventually, most vehicles will likely be electric. With the continued development of electric vehicle technology, there is a need to provide improved power sources (e.g., battery systems or modules). For example, it is desirable to increase the distance such vehicles can travel without requiring charging of the battery, to improve the performance of such batteries, and to reduce the cost and time associated with battery charging.

The current trend is toward battery electric vehicles that almost fully utilize lithium ion battery technology. Lithium ion batteries have many advantages over comparable nickel metal hydride batteries, but unlike nickel metal hydride batteries, lithium ion batteries are more susceptible to changes in battery temperature and require very stringent thermal management requirements. For example, operating temperatures below 10 ℃ are inefficient, while the optimum cell operating temperature is in the range of 10 to 35 ℃. As temperatures increase from 35 to 70 ℃, cells operate less efficiently and operating at these temperatures damages the cells over time. Temperatures in excess of 70 ℃ present a significant risk of thermal runaway. As a result, lithium ion batteries require systems to regulate their temperature during vehicle operation. In addition, up to 10% of the input power ends up as heat during charging. As rapid charging of lithium ion batteries becomes more prevalent, there remains a need for an effective system for battery thermal management.

Dispersions of paraffin wax in aqueous solution have been used as Phase Change Material (PCM) slurries or liquid coolants. These slurries and liquid coolants have been proposed for use as thermal management fluids in batteries, such as lithium ion batteries. Due to the high melting enthalpy of the melting, the paraffin wax dispersion increases the heat capacity of the thermal management fluid in the temperature range in which the paraffin wax melts. This latent heat effect allows the thermal management fluid to remove thermal energy from a hot surface without substantially increasing the temperature of the fluid (i.e., as a more efficient coolant).

Disclosure of Invention

While phase change material coolants are promising, there are two key disadvantages that may prevent their use in coolant systems. First, in its use as a phase change material coolant, the coalescence of molten paraffin has a great disadvantage. In particular, the coalescence of the molten paraffin causes the deposition of solid paraffin in the cooling system and eventually blocks the cooling system. The dispersed paraffin particles then increase the viscosity of the fluid. In general, the viscosity of the phase change material coolant increases with increasing paraffin content and increasing paraffin particle size. This is detrimental to the thermal conductivity of the fluid, as heat can diffuse more quickly through a low viscosity fluid. Thus, phase change material coolant is a trade-off between two key (critical) properties of coolant fluids — heat capacity and thermal conductivity. It would therefore be advantageous to provide a thermal management fluid that can overcome these disadvantages.

The present inventors have found simple and cost effective emulsions with improved phase change material dispersibility. The improved dispersibility in turn reduces the tendency of the dispersed phase change material (e.g., paraffin wax) to coalesce when melted. In addition, the phase change material is formulated into micelles with very small diameters and very narrow size distributions, which in turn allows the emulsions of the present disclosure to have improved viscosity, and thus thermal diffusivity. The smaller micelle size also allows for a higher concentration of phase change material in the emulsion and thus improves the heat capacity of the emulsion. The higher number of micelles with small diameters and narrow size distributions in comparison results in an increased surface area of the micelles, which in turn allows for a faster temperature response and improved thermal conductivity of the emulsion. Phase change materials absorb heat through the effect of latent heat of fusion in a desired temperature range.

Accordingly, one aspect of the present disclosure provides an emulsion comprising:

an aqueous carrier fluid; and

a micelle dispersion in an aqueous carrier fluid, wherein each micelle comprises a solid hydrophobic core particle comprising a phase change material and one or more emulsifiers forming a micelle shell around the solid hydrophobic core particle, wherein the micelles have an average particle size diameter in the range of about 0.1 μm to about 1.5 μm (e.g., preferably in the range of about 0.25 μm to about 1.0 μm).

The emulsions of the present disclosure may be provided in various concentrations. For example, in certain embodiments, the emulsions of the present disclosure are provided in a concentration suitable for use as a thermal management fluid concentrate, i.e., a concentration that can be diluted with an aqueous medium to provide a thermal management fluid. In other embodiments, the emulsions of the present disclosure are provided in concentrations that are themselves suitable for use as thermal management fluids (e.g., fully formulated thermal management fluids).

Another aspect of the present disclosure provides a method for preparing an emulsion, the method comprising: combining a first fluid comprising one or more emulsifiers dissolved in an aqueous carrier fluid with a second fluid comprising one or more phase change materials; and contacting the first fluid with the second fluid under shear forces to produce an intermediate fluid; and recovering the emulsion from the intermediate fluid.

Another aspect of the disclosure provides a method comprising

Passing an emulsion or thermal management fluid of the present disclosure over a surface; and

absorbing thermal energy from the thermal management fluid from the surface.

In another aspect, the present disclosure provides a battery pack, including:

a housing;

one or more electrochemical cells disposed in the housing;

a fluid path extending through the housing and in sufficient thermal communication with the one or more electrochemical cells; and

the emulsions or thermal management fluids of the present disclosure.

In another aspect, the present disclosure provides a thermal management circuit comprising:

a fluid path extending around and/or through the electrical component;

a heat exchanger;

a pump;

at least one conduit connecting the fluid path, the heat exchanger, and the pump; and

the emulsions or thermal management fluids of the present disclosure,

wherein the thermal management fluid is disposed in the fluid path, the heat exchanger, the pump, and the conduit.

Drawings

The accompanying drawings are included to provide a further understanding of the compositions and methods of the disclosure, and are incorporated in and constitute a part of this specification. The figures are not necessarily to scale and the dimensions of the various elements may be distorted for clarity. The drawings illustrate one or more embodiments of the disclosure and, together with the description, serve to explain the principles and operations of the disclosure.

Fig. 1 is a schematic cross-sectional view of a thermal management circuit according to an embodiment of the present disclosure.

Fig. 2 is a schematic cross-sectional view of a thermal management circuit according to another embodiment of the present disclosure.

FIG. 3 is a graph showing the change in specific heat capacity of the emulsion of example 1 at a temperature of-80 ℃ to +80 ℃. The data is a superposition of three different measurements made on the same material.

Detailed Description

The particulars shown herein are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the various embodiments of the present invention. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for a fundamental understanding of the present invention, the description taken with the drawings and/or examples making apparent to those skilled in the art how the several forms of the present invention may be embodied in practice. Thus, before the disclosed processes and devices are described, it is to be understood that the aspects described herein are not limited to particular embodiments, devices, or configurations, and, thus, may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to be limiting unless specifically defined herein.

The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following examples and claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each separate value is incorporated into the specification as if it were individually recited herein. Ranges may be expressed herein as from "about" one particular value, and/or to "about" another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

Throughout the specification and claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, unless the context clearly requires otherwise; that is, in the sense of "including, but not limited to". Words using the singular or plural number also include the plural and singular number, respectively. Additionally, the words "herein," "above" and "below," and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application.

As will be appreciated by one of ordinary skill in the art, each of the embodiments disclosed herein may include, consist essentially of, or consist of the elements, steps, ingredients, or components it specifically specifies. As used herein, the transitional phrase "comprising" is intended to include, but not be limited to and allow for even the inclusion of unspecified elements, steps, ingredients or components in large quantities. The transitional phrase "consisting of … …" does not include any elements, steps, ingredients, or components not specified. The transitional phrase "consisting essentially of … …" limits the scope of the embodiments to the specified elements, steps, ingredients, or components and those that do not materially affect the embodiments.

Unless otherwise indicated, all numbers expressing quantities of ingredients, properties (such as molecular weight), reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. When further clarification is desired, the term "about" has the meaning reasonably given to it by those skilled in the art, when used in conjunction with a stated numerical value or range, i.e., meaning slightly greater than or slightly less than the stated value or range, at ± 20% of the stated value; ± 19% of said value; ± 18% of said value; ± 17% of said value; ± 16% of said value; ± 15% of said value; ± 14% of said value; ± 13% of said value; ± 12% of said value; ± 11% of said value; ± 10% of said value; ± 9% of said value; ± 8% of said value; ± 7% of said value; ± 6% of said value; ± 5% of said value; ± 4% of said value; ± 3% of said value; ± 2% of said value; or within ± 1% of said value.

All percentages, ratios, and proportions herein are by weight unless otherwise specified.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group item may be referred to and claimed individually or in any combination with other items in the group or other elements found herein. It is contemplated that one or more items in a group may be included in, or deleted from, a group for convenience and/or patentability. When any such inclusion or deletion occurs, the specification is considered to encompass the modified group, and thus satisfies the written description of all Markush (Markush) groups used in the appended claims.

Certain embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Of course, variations of those described embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Throughout this specification, reference is made to patents and published publications (publications) for a number of times. Each of the cited references and published publications is individually incorporated by reference herein in its entirety.

Finally, it is to be understood that the embodiments of the invention disclosed herein are illustrative of the principles of the invention. Other modifications that may be employed are within the scope of the invention. Thus, by way of example, and not limitation, alternative configurations of the present invention may be used in accordance with the teachings herein. Accordingly, the invention is not limited to what has been particularly shown and described.

In general, the disclosed materials and methods and apparatus provide improvements in emulsions (e.g., suitable for use as thermal management fluids) that reduce the tendency of dispersed phase change materials (e.g., paraffin wax) to coalesce when melted. In addition, the phase change material is formulated into micelles having a very small diameter and a very narrow size distribution, which in turn allows the emulsions of the present disclosure to have improved viscosity, and thus thermal conductivity. The smaller micelle size also allows for a higher concentration of phase change material in the emulsion and thus improves the heat capacity of the emulsion. The higher number of micelles with small diameter and narrow size distribution results in an increased surface area of the micelles, which in turn allows for a faster temperature response and improved thermal conductivity of the emulsion. Phase change materials absorb heat via the effect of latent heat of fusion within a desired temperature range, such that the material in solid phase form melts at a particular temperature, thus absorbing heat and entering the liquid phase. Once the emulsion cools below the melting point, the phase change material in the liquid phase solidifies into a solid phase ready for use during a subsequent heating cycle of the emulsion. It is also possible to provide an emulsion comprising various phase change materials, each phase change material having a different melting point and/or mass, such that the solid phase change material enters the liquid phase over a range of temperatures. This results in an emulsion that can provide a constant or varying cooling effect as desired. For example, a wax having a lower melting point may be suitable for general use, a wax having a medium melting point may be suitable for charging a battery, and a wax having a higher melting point is used to prevent thermal runaway in the battery. It may also be desirable to be able to pass the emulsion through a heat exchanger to provide a cooling effect by, for example, dissipating heat from the battery.

Accordingly, one aspect of the present disclosure provides an emulsion comprising:

an aqueous carrier fluid; and

a micelle dispersion within an aqueous carrier fluid, wherein each micelle comprises a solid hydrophobic core particle comprising a phase change material and one or more emulsifiers forming a micelle shell around the solid hydrophobic core particle, wherein the micelles have an average particle size diameter in the range of about 0.1 μm to about 1.5 μm.

As one of ordinary skill in the art will appreciate, a micelle is an aggregate of emulsifier molecules dispersed in a colloid, wherein particles of a first material are suspended in a second material, thereby forming a two-phase system. Unlike a solution, the first material is insoluble or immiscible in the second material (i.e., it becomes an emulsion). In aqueous solution, micelles form aggregates with the hydrophobic tails of the emulsifier molecules facing inwards and the hydrophilic heads of the emulsifier molecules facing outwards. This forms normal phase micelles, resulting in an oil-in-water phase mixture. Reverse micelles have the opposite structure, with the hydrophilic head of the emulsifier molecule facing inwards and the hydrophobic tail facing outwards. This results in a water-in-oil phase mixture. The filling behavior of the emulsifier molecules may result in a monolayer of emulsifier molecules around the micelle core, which may typically form spheres in view of the surface energy. Thus, in certain embodiments, the micelles of the present disclosure are substantially spherical in structure. In this example, an oil-in-water system is contemplated, as the phase change material is a solid oily (waxy) material.

Additional layers of emulsifier may also be packed around the exterior of the micelle. This will be the case when additional emulsifier is added to the mixture. For example, when a shear force is applied to the phase change material, the molecules of the phase change material stretch. This stretching causes the molecules to flatten and form a layered structure, thus increasing the surface area to which any emulsifier can be attracted. In combination with a laminar flow of dispersion molecules around the emulsifier in water, the filling fraction of the emulsifier increases from ≦ 1/3 to > 1/2. Once the shear force is removed from the molecule, it will form spherical micelles due to surface energy considerations, unless, of course, the structure of the emulsifier causes the smallest surface energy configuration of the micelle to be lamellar or cylindrical. For example, gemini emulsifiers (sometimes referred to as dimer emulsifiers) have two hydrophobic tails that distort the micelle core into an elongated ovoid shape. For spherical micelles, the packed portion of the emulsifier then drops back to ≦ 1/3, so any emulsifier attracted to the temporary lamellar structure of the molecule forms an additional layer of emulsifier around the micelle. However, only the odd-numbered layers are formed because, for the normal-phase micelle, the even-numbered layers of the emulsifier molecules are arranged such that the hydrophilic head is in contact with the hydrophilic head of the first layer of the emulsifier molecules, and the hydrophobic tail is directed outward. For reversed micelles, the opposite is applicable (true). Thus, in both cases, the micelle will have 1, 3, 5, 7, … … n =2k +1 layers of emulsifier. This also results in no free emulsifier in any form in the emulsion, since the emulsifier will be bound in multiple layers within these micelles. As mentioned above, unbound emulsifier is substantially absent from the aqueous solution. The more emulsifier added to the emulsion-the greater the number of layers of emulsifier in the micelles. Thus, in certain embodiments, the emulsifier molecules are disposed around the hydrophobic core in a single molecular layer. In certain other embodiments, the emulsifier molecules are disposed around the hydrophobic core in three or more molecular layers. In certain embodiments, different molecular layers may include two or more emulsifiers. For example, a nonionic emulsifier may be present in the surface layer, and an ionic emulsifier may be present in the layer.

One advantage of the fluids and methods of the present disclosure is the uniformity of the size of the micelles in the emulsion. The distribution of the average diameter of the micelles follows a gaussian distribution. The average micelle diameter is the average of the various diameter measurements made on micelles, which in the case of spherical micelles is approximately equal to the micelle diameter (since there is little or no change in diameter wherever the measurement is made).

As described above, the inventors have noted that the use of micellar emulsions having a relatively narrow micelle size distribution can result in a number of advantages. As one of ordinary skill in the art will appreciate, micelle size distribution can be characterized by d50, d10, and d90 values, where d50 is the median particle size, d10 is the particle size at the 10 th percentile of the particles in size order, and d90 is the particle size at the 90 th percentile of the particles in size order. In certain embodiments, the micelles of a particular emulsion as further described herein have a d50 value in the range of 0.1 μm to 1.5 μm; for example, 0.1 μm to 1.2 μm, or 0.1 μm to 1.0 μm, or 0.1 μm to 0.5 μm, or 0.1 μm to 0.4 μm, or 0.2 μm to 1 μm, or 0.2 μm to 0.8 μm, or 0.2 μm to 0.6 μm, or 0.2 μm to 0.5 μm, or 0.2 μm to 0.4 μm, or 0.4 μm to 1 μm, or 0.4 μm to 0.8 μm, or 0.4 μm to 0.6 μm, or 0.4 μm to 0.5 μm, or 0.3 μm to 0.5 μm, or 0.35 μm to 0.45 μm. In certain embodiments, d10 is no less than 50% of d50, and d90 is no greater than 150% of d 50. In certain embodiments, d10 is not less than 60% of d50, and d90 is not greater than 140% of d 50. In certain embodiments, d10 is no less than 70% of d50, and d90 is no greater than 130% of d 50. In certain embodiments, d10 is no less than 75% of d50, and d90 is no greater than 125% of d 50. In certain embodiments, d10 is not less than 80% of d50, and d90 is not greater than 120% of d 50.

In certain embodiments, the micelles have an average diameter of no more than 1.5 μm; for example, an average diameter in the range of 0.1 μm to 1.5 μm; for example, 0.1 μm to 1.2 μm, or 0.1 μm to 1.0 μm, or 0.1 μm to 0.5 μm, or 0.1 μm to 0.4 μm, or 0.2 μm to 1 μm, or 0.2 μm to 0.8 μm, or 0.2 μm to 0.6 μm, or 0.2 μm to 0.5 μm, or 0.2 μm to 0.4 μm, or 0.4 μm to 1 μm, or 0.4 μm to 0.8 μm, or 0.4 μm to 0.6 μm, or 0.4 μm to 0.5 μm, or 0.3 μm to 0.5 μm, or 0.35 μm to 0.45 μm. In certain embodiments, a particularly preferred average diameter is in the range of 0.1 μm to 1.0 μm.

While there are many suitable measurement techniques to determine micelle particle size and micelle particle size distribution, for purposes of this disclosure, laser particle size analysis using a beckmann coulter PS analyzer (LS 13320) is used for quantification. The method uses Fraunhoffer diffraction and Polarized Intensity Differential Scanning (PIDS) to determine particle size.

As described above, the micelle of the present disclosure includes a phase change material. As used herein, a phase change material is a material with a high heat of fusion (e.g., greater than 100kJ/kg, or greater than 150kJ/kg, or even greater than 200kJ/kg) that melts and solidifies at certain temperatures, capable of storing and releasing energy. Various phase change materials known in the art may be suitably used in the practice of the present invention. Desirably, the phase change materials suitable for use in the micelles of the present disclosure will be thermally cyclable, non-hazardous or non-toxic, and non-reactive or inert with respect to other battery components. In certain embodiments, the phase change material is a waxy, wax-based, or waxy material.

The selection of a suitable phase change material will depend on the end use application of the fluid of the present disclosure. The phase change material may be a fully formulated waxy material or may be a blend of components, at least one of which is waxy. In certain embodiments, the phase change material may be selected from the group consisting of paraffin waxes, microcrystalline waxes, polyethylene waxes, ester waxes, fatty acids, fatty amide containing materials, sulfonamide materials, resinous materials made from different natural sources (e.g., tall oil rosins and rosin esters), synthetic resins, oligomers, polymers, and copolymers, and combinations thereof.

In certain embodiments, the phase change material is paraffin. Paraffin wax consists of a mixture of mostly linear alkanes having 14 to 40 carbon atoms. Commercially available paraffins may be fully refined grades (i.e., containing less than 0.5% oil), semi-refined grades (i.e., containing in the range of 0.5% and 1.5% oil), flake wax grades (i.e., containing in the range of 0.5% to 5% oil), and slack wax grades (i.e., containing in the range of 5% to 20% oil). One skilled in the art will recognize that the selection of an appropriate paraffin wax for size and grade will depend on the desired properties of the emulsion. Some commercial sources include, for example, Parafol and Sasolwax brands (available from Sasol, Germany), Inderawax brands (available from Industrial Rawmaterials LLC of Prain Veu, N.Y.), Paraffin available from BASF of Germany, and Parvan ^TMA brand of paraffin wax (available from Exxon Mobil Corporation, europe, tx).

In certain embodiments, the phase change material may be selected from the group consisting of 1-cyclohexyloctadecane, 4-heptanedione, quinones, benzamides, and mixtures thereof. In certain embodiments, the phase change material may be a paraffin wax in combination with one or more of 1-cyclohexyloctadecane, 4-heptanedione, quinone, and benzamide.

The choice of phase change material may also depend on the thermal management application and the operating temperature of the device. Thus, in certain embodiments, the phase change material has a melting point of at least 30 ℃; for example, at least 35 ℃, or at least 40 ℃, or at least 50 ℃, or at least 60 ℃, or at least 70 ℃, or in the range of 30 ℃ and 100 ℃, or in the range of 30 ℃ to 90 ℃, or in the range of 30 ℃ to 80 ℃, or in the range of 30 ℃ to 75 ℃, or in the range of 30 ℃ to 70 ℃, or in the range of 30 ℃ to 65 ℃, or in the range of 30 ℃ to 60 ℃, or in the range of 35 ℃ to 100 ℃, or in the range of 35 ℃ to 90 ℃, or in the range of 35 ℃ to 80 ℃, or in the range of 35 ℃ to 75 ℃, or in the range of 35 ℃ to 70 ℃, or in the range of 35 ℃ to 65 ℃, or in the range of 35 ℃ to 60 ℃, or in the range of 40 ℃ to 100 ℃, or in the range of 40 ℃ to 90 ℃, or in the range of 40 ℃ to 80 ℃, or in the range of 40 ℃ to 75 ℃ to 70 ℃, or in the range of from 40 ℃ to 65 ℃, or in the range of from 40 ℃ to 60 ℃, or in the range of from 50 ℃ to 100 ℃, or in the range of from 50 ℃ to 90 ℃, or in the range of from 50 ℃ to 80 ℃, or in the range of from 50 ℃ to 75 ℃, or in the range of from 50 ℃ to 70 ℃, or in the range of from 50 ℃ to 65 ℃, or in the range of from 50 ℃ to 60 ℃.

Notably, the present inventors have determined that while high viscosity or solid phase additives such as waxes (e.g., paraffin waxes) are generally difficult to emulsify, they can be successfully and stably emulsified using the methods described herein. In certain embodiments, the emulsion may have a total viscosity value of about 3.4cP at 30 ℃ (according to ASTM D455), similar to 60/40 water/glycol coolant.

The emulsion of the present disclosure may include one phase change material (i.e., the micelle of the present disclosure includes one phase change material). The emulsions of the present disclosure may also include two or more different phase change materials. For example, in certain embodiments, the micelles comprise a first set of micelles having solid hydrophobic core particles comprising a first phase change material, and a second set of micelles having solid hydrophobic core particles comprising a second phase change material different from the first phase change material. The first phase change material and the second phase change material may have substantially the same melting points (e.g., no more than 5 ℃ difference in melting points, or no more than 2 ℃ difference in melting points, or no more than 1 ℃ difference in melting points). The first phase change material and the second phase change material may also have different melting points (e.g., melting points that differ by at least 10 ℃, or melting points that differ by at least 20 ℃, or melting points that differ by at least 50 ℃).

In certain embodiments of the present disclosure, the emulsion includes the phase change material in an amount ranging from about 10wt% to about 60wt% based on the total weight of the emulsion. For example, in certain embodiments of the emulsions as otherwise described herein, the phase transfer material is present in an amount of from about 10wt% to about 50wt%, or from about 10wt% to about 30wt%, or from about 10wt% to about 15wt%, or from about 40wt% to about 60wt%, or from about 45wt% to about 55wt%, or from about 50wt% to about 60wt%, or from about 50wt% to about 55 wt%. A particularly preferred embodiment employs a wax content of about 53.9% by weight.

As described above, the emulsions of the present disclosure include one or more emulsifiers. The inventors have found that in certain embodiments, one or more emulsifiers are substantially incorporated into the micelles. For example, in certain embodiments, no more than 1wt% of the one or more emulsifiers in the emulsion are present in an unbound state (i.e., not part of the micelles) based on the total weight of the emulsion. In certain embodiments, no more than 0.5wt%, or no more than 0.1wt%, or no more than 0.05wt%, or even no more than 0.01wt% of the emulsion in the emulsion is present in an unbound state, based on the total weight of the emulsion. The point at which the emulsion becomes substantially free of excess emulsifier can be determined by measuring the surface tension of the emulsion. Once the critical micelle concentration is reached and no more emulsifier molecules are included in the surface layer, the surface tension of the emulsion exhibits discontinuities. This can be detected by surface tension measurement techniques known to those skilled in the art. Other techniques for determining this include Nuclear Magnetic Resonance (NMR) techniques and light scattering techniques. These include those taught in James-Smith et al, Journal of Colloid and Interface Science, 310: 590-.

In certain desirable embodiments as further described herein, the emulsion is substantially free of antifoaming agents and antifoaming compounds. The present inventors have determined that the emulsification techniques described herein can provide emulsions that do not foam easily, although not including a large amount of defoamer/defoaming compound. For example, in certain embodiments, the emulsions of the present disclosure include no more than 2wt% of one or more defoamers and defoaming compounds, for example, no more than 1wt%, or no more than 0.5wt%, or no more than 0.1wt%, or no more than 0.01wt%, or no more than 0.005wt%, or even no more than 0.001wt%, based on the total weight of the emulsion.

Typical defoamer/defoamer compositions commonly used in metalworking fluids include organically modified silicone defoamers, PDMS (polydimethylsiloxane) defoamers, and wax defoamers. Organically modified silicone defoamers and PDMS defoamers are based on a polysiloxane backbone. In PDMS defoamers, only methyl and oxygen are bonded to the silicon atom. In organomodified silicone defoamers, organic side chains (such as ethylene oxide/propylene oxide copolymers) are chemically bonded to a polysiloxane backbone. Typical wax defoamers include, but are not limited to, Ethylene Bis Stearamide (EBS), paraffin waxes, ester waxes, and fatty alcohol waxes. For each type of defoamer/defoamer, the foam is broken by the hydrophobic solid material in the defoamer/defoamer, breaking the film that forms between the defoamer/defoamer material and the foam droplets. In certain embodiments as further described herein, the emulsions of the present disclosure include no more than 1wt% in total of organically modified silicone defoamer, PDMS (polydimethylsiloxane) defoamer, and wax defoamer, or no more than 2wt% of one or more defoamers and defoaming compounds, based on the total weight of the emulsion, for example, no more than 1wt%, or no more than 0.5wt%, or no more than 0.1wt%, or no more than 0.01wt%, or no more than 0.005wt%, or even no more than 0.001 wt%.

Emulsifiers suitable for use in embodiments of the present disclosure include all those emulsifiers that are oil soluble with the polar head component, including those having the general structure of a hydrocarbyl-aryl-polyether group. One particularly useful wax emulsifier is one that includes a mixture of alkyl and alkylaryl ethoxylates (such as alkylphenol ethoxylates). In certain embodiments, the emulsifier may comprise a surfactant. Based on the disclosure herein, one of ordinary skill in the art will select the desired emulsifier.

In certain embodiments of the present disclosure, the emulsions of the present disclosure comprise one or more emulsifiers in an amount ranging from about 0.1wt% to about 10wt% based on the total weight of the emulsion. For example, in certain embodiments of the emulsions as further described herein, the one or more emulsifiers are present in an amount of from about 0.1wt% to about 8wt%, or from about 0.1wt% to about 5wt%, or from about 0.1wt% to about 2wt%, or from about 0.1wt% to about 1wt%, or from about 0.2wt% to about 10wt%, or from about 0.2wt% to about 8wt%, or from about 0.2wt% to about 5wt%, or from about 0.2wt% to about 2wt%, or from about 0.2wt% to about 1wt%, or from about 0.5wt% to about 10wt%, or from about 0.5wt% to about 8wt%, or from about 0.5wt% to about 5wt%, or from about 0.5wt% to about 2wt%, or from about 1wt% to about 10wt%, or from about 1wt% to about 8wt%, or from about 1wt% to about 5wt%, or from about 2wt% to about 10wt%, or from about 2wt% to about 8wt%, based on the total weight of the emulsion. As will be appreciated by one of ordinary skill in the art, the amount of the one or more emulsifiers may increase or decrease directly with the weight% of the phase change material.

As will be appreciated by one of ordinary skill in the art, the ratio of the amount of phase change material to the amount of emulsifier will be a factor in determining micelle size. In certain embodiments as further described herein, the weight ratio of the amount of phase change material to the amount of emulsifier is in the range of about 1 to about 10, or about 1 to 8, or about 2 to 10.

In certain embodiments of the present disclosure, the aqueous carrier fluid may be water. In certain embodiments, the aqueous carrier fluid may be water and one or more of glycerol, methanol, ethylene glycol, propylene glycol, and diethylene glycol. In certain embodiments, one or more of glycerol, methanol, ethylene glycol, propylene glycol, and diethylene glycol may be present in an amount of about 1 to 10wt%, based on the total weight of the aqueous carrier fluid.

As one of ordinary skill in the art will appreciate based on the present disclosure, the emulsions of the present disclosure may also include a variety of other components, such as those conventional in compositions for thermal management applications. Examples include, but are not limited to, corrosion inhibitors, preservatives, biocides, and combinations thereof.

In certain embodiments, the emulsion may further include one or more corrosion inhibitors, preservatives, biocides, and combinations thereof, for example, present in an amount up to 5.0wt%, based on the total weight of the emulsion. In certain such embodiments, one or more of a corrosion inhibitor, a preservative, a biocide, and combinations thereof is present in an amount in the range of about 0.1wt% to about 5.0wt%, or about 1.0wt% to about 5.0wt%, or about 0.1wt% to about 1.0wt%, based on the total weight of the emulsion.

One of ordinary skill in the art will appreciate that a variety of other components may be present in the emulsions of the present disclosure.

In certain embodiments of the present disclosure, the emulsions of the present disclosure may have a heat capacity ranging from about 1J/gK to about 50J/gK. For example, in certain embodiments of the emulsions as further described herein, the heat capacity is in a range of from about 1J/gK to about 30J/gK, or from about 1J/gK to about 20J/gK, or from about 1J/gK to about 15J/gK, or from about 1J/gK to about 10J/gK, or from about 3J/gK to about 30J/gK, or from about 3J/gK to about 20J/gK, or from about 3J/gK to about 15J/gK, or from about 3J/gK to about 10J/gK, or from about 2J/gK to about 5J/gK, or from about 3J/gK to about 4J/gK.

In certain embodiments of the present disclosure, the emulsions of the present disclosure may have a thermal conductivity of from about 0.05W/mK to about 1W/mK. For example, in certain embodiments of the emulsions as further described herein, the thermal conductivity is in a range of from about 0.25W/mK to about 1W/mK, or from about 0.5W/mK to about 1W/mK, from about 0.75W/mK to about 1W/mK, or from about 0.05W/mK to about 0.5W/mK.

In certain embodiments of the present disclosure, the emulsion of the present disclosure may have a kinematic viscosity at 30 ℃ of from about 1 to about 10cSt, e.g., from about 1 to about 9cSt, or from about 1 to about 8cSt, or from about 1 to about 7cSt, or from about 1 to about 6cSt, or from about 5 to about 10cSt, or from about 5 to about 9cSt, or from about 5 to about 8cSt, or from about 5 to about 7cSt, as measured according to ASTM D455.

As described above, the emulsions of the present disclosure can be provided in various concentrations. In certain embodiments, the emulsions of the present disclosure are provided in concentrations suitable per se for use as thermal management fluids/the emulsions can be used undiluted in thermal management applications. Accordingly, another aspect of the present disclosure is a thermal management fluid in the form of an emulsion of the present disclosure.

And in other embodiments, the emulsions of the present disclosure are provided in a concentration suitable for use as a thermal management fluid concentrate, i.e., in a concentration that can be diluted with other media (e.g., water, or a combination of water and one or more of glycerol, methanol, ethylene glycol, propylene glycol, and diethylene glycol) to provide a thermal management fluid. Salts such as potassium formate may be used to lower the freezing point of the emulsion.

Thus, the emulsion of the present disclosure may also be provided by diluting a higher concentration emulsion (e.g., a higher concentration emulsion of the present disclosure).

In one exemplary embodiment, the emulsion of the present disclosure comprises: in the range of about 10 to about 60wt% phase change material; an emulsifier in the range of about 5 to about 10 wt%; glycerol in the range of about 0 to about 50 wt%; other additives in the range of about 0 to about 5 wt%; and the remaining water. In certain such embodiments, ethylene glycol or propylene glycol may be substituted for glycerol. In certain such embodiments, the emulsion may further comprise other freezing point depressants, such as salts, in the range of about 0 to about 25 wt%. In certain such embodiments, various additives used in conventional water-based coolants may also be included in the emulsion. Such emulsions may be used, for example, as concentrates for thermal management fluids.

Accordingly, another aspect of the present disclosure is a thermal management comprising the emulsion of the present disclosure, for example, prepared by combining the emulsion of the present disclosure with an aqueous fluid. The emulsions of the present disclosure may be diluted, for example, with a desired amount of water. In certain embodiments, the emulsion is used in an amount of about 1wt% to about 50wt%, based on the total weight of the thermal management fluid; for example, from about 5wt% to about 30wt%, or from about 5wt% to about 20wt%, or from about 20wt% to about 30 wt%. In certain embodiments, dilution may be performed more than once; for example, the process can be effective to form a series of thermal management fluids, where each subsequent fluid has a lower concentration of the emulsion of the present disclosure. One skilled in the art can dilute the thermal management fluid until the desired thermal management performance is achieved.

One suitable method of preparing the emulsion of the present disclosure is described in U.S. patent application publication No. 2013/0201785, which is hereby incorporated by reference in its entirety. This publication discloses an apparatus for mixing a phase change material and an aqueous material under shear and laminar flow to produce an oil-in-water or water-in-oil fluid. Accordingly, one aspect of the present disclosure provides a method of making an emulsion of the present disclosure, the method comprising obtaining a first fluid comprising one or more emulsifiers dissolved in an aqueous carrier fluid (e.g., water); obtaining a second fluid comprising a phase change material; the first fluid is contacted with the second fluid under shear forces to produce an intermediate fluid. The intermediate fluid may be in the form of a colloidal emulsion, and may be free-flowing or gelatinous. The intermediate fluid may also have a greater viscosity than the first fluid or the second fluid, e.g., at least 5% higher, or at least 10% higher, or at least 50% higher. The intermediate fluid may comprise micelles of the phase change material in an aqueous carrier fluid. Both the first fluid and the second fluid may be added to a chamber in which an agitator is used to mix the two fluids together under shear forces by rotating at a rotational speed of about 1200 to about 1600 rpm. The shape of the chamber and the size of the stirrer can be selected to ensure that the area surrounding the chamber walls is free of turbulence. Thus, when the phase change material is under shear, an aqueous suspension of the emulsifier can flow around the chamber in this region, thereby creating a laminar flow. In certain embodiments, the third fluid may be added to the intermediate fluid under laminar flow (e.g., increasing the water content of the aqueous carrier fluid to reduce the viscosity of the resulting emulsion).

The method of the present disclosure allows for the emulsification of materials with high viscosity into stable emulsions. It is currently difficult to emulsify fluids having viscosities greater than about 100 to 150cSt at 40 ℃ using current technology. The methods of the present disclosure can be used to emulsify fluid and solid phase materials having viscosities of 8000 to 12000cSt at 40 ℃. The practical limit depends on the temperature of the various components during emulsification. For example, it may be necessary to heat the components up to about 90 ℃ to achieve emulsification.

In certain other aspects, the present disclosure provides a method of making an emulsion of the present disclosure, the method comprising: obtaining a first fluid comprising one or more emulsifiers; obtaining a second fluid comprising a phase change material; contacting the first fluid with the second fluid under shear forces to produce an intermediate fluid; and contacting the intermediate fluid with an aqueous carrier fluid (e.g., water) under laminar flow to obtain an emulsion. The intermediate fluid may have a greater viscosity than the first fluid or the second fluid, e.g., at least 5% higher, or at least 10% higher, or at least 50% higher. Both the first fluid and the second fluid may be added to a chamber in which an agitator is used to mix the two fluids together under shear forces by rotating at a rotational speed of about 1200 to about 1600 rpm.

Another aspect of the present disclosure provides a method comprising passing a thermal management fluid according to any of the embodiments described above over a surface and absorbing thermal energy in the thermal management fluid from the surface. Referring to fig. 1, an embodiment of such a method is shown. The thermal management circuit 100 is shown in fig. 1 in a schematic cross-sectional side view. The thermal management circuit 100 includes a thermal management fluid 120 that circulates through the circuit and passes over the surface 142. The temperature of the surface 142 increases compared to the temperature of the thermal management fluid 120. As a result, thermal energy is absorbed in the thermal management fluid 120 from the surface 142.

In certain embodiments as further described herein, the method includes generating thermal energy by operating the electrical component. For example, the thermal management circuit 100 is associated with an electrical component 140 that generates heat during operation. In certain embodiments, heat is generated as a factor of the charging and discharging of the electrical components. As will be appreciated by those of ordinary skill in the art, when current is passed through the loops and elements of an electrical component, inefficiencies in the operation of the electrical component and electrical resistance in the loop corresponding to the loop generate heat. For example, heat from operation of the electrical component 140 causes the temperature of the surface 142 to increase, which then causes transfer of thermal energy to the thermal management fluid 120. In other embodiments, the thermal energy is generated by a chemical reaction (such as an exothermic reaction) or by friction. In still other embodiments, the thermal management fluid cools and absorbs thermal energy from the surface at ambient or slightly elevated temperatures.

In certain embodiments as further described herein, the electrical component comprises a battery, a capacitor, a fuel cell, a motor, or a computer. For example, in certain embodiments, the electrical component is a battery pack comprising one or more electrochemical cells disposed in a housing. In other embodiments, the electrical component is one or more capacitors, such as an electrolytic capacitor or an electric double layer capacitor, e.g., a supercapacitor. In still other embodiments, the electrical component is one or more fuel cells, such as a polymer electrolyte membrane fuel cell, a direct methanol fuel cell, an alkaline fuel cell, a phosphoric acid fuel cell, a molten carbonate fuel cell, a solid oxide fuel cell, or a reversible fuel cell. In certain embodiments, the electrical component is an electric motor. In still other embodiments, the electrical component is a computer, such as a personal computer or a server.

In certain embodiments as otherwise described herein, the surface is a surface of an electrical component. For example, in fig. 1, the housing 150 of the electrical component 140 contains a reservoir of the thermal management fluid 120. The elements of the electrical components, including certain circuits that generate heat, are immersed in the thermal management fluid 120, and the thermal management fluid absorbs thermal energy directly from the outer surface 142 of the electrical components 140.

In certain embodiments as further described herein, the surface is an inner surface of the conduit. For example, fig. 2 shows a thermal management circuit 200 that includes an electrical component 240 that includes a plurality of individual cells 244. In particular, the electrical component 240 is a battery that includes a plurality of electrochemical cells 244. The electrical component 240 also includes a conduit 246 that extends through the interior of the electrical component and between the electrochemical cells 244. As the electrical components generate thermal energy, the inner surface 242 of the conduit 246 is heated and the thermal energy is absorbed by the thermal management fluid 220.

In certain embodiments as further described herein, the conduit passes through a housing surrounding the electrical component. For example, the conduit 246 in the thermal management circuit 200 extends through an aperture 252 in a housing 250 surrounding the electrical component 240, which allows the thermal management fluid 220 to be delivered to other elements of the thermal management circuit 200.

Another aspect of the present disclosure provides a battery pack including: a housing; one or more electrochemical cells disposed in the housing; a fluid path extending through the housing and in sufficient thermal communication with the one or more electrochemical cells; and a thermal management fluid according to any of the embodiments described above, disposed in the fluid path. For example, thermal management circuit 200 in fig. 2 includes a battery pack 210. The battery pack includes a plurality of electrochemical cells 244 disposed within a housing 250. The conduit 246 forms a fluid path extending through the housing. The thermal management fluid 220 disposed in the conduit 246 is thereby placed in thermal communication with the electrochemical cell 244. As the electrochemical cells 244 are charged and discharged, the heat they generate is absorbed by the thermal management fluid 220. In certain embodiments, the electrochemical cell is subjected to a rapid charge, which generates a large amount of heat. The high thermal capacity of the thermal management fluid enables the rapid absorption of this large amount of heat as it is generated.

In certain embodiments as otherwise described herein, the fluid path is at least partially defined by the cavity of the housing. For example, in certain embodiments, similar to the fluid path 122 in the member 140, at least a portion of the fluid path is formed between the electrochemical cell and the inner wall of the housing.

In certain embodiments as further described herein, the fluid path is at least partially defined by at least one conduit disposed in the housing. For example, in the battery pack 210, the conduit 246 provides the fluid path 222 through the housing 250.

In certain embodiments as further described herein, the electrochemical cell is a lithium ion electrochemical cell. In other embodiments, the electrochemical cell is an aluminum ion cell, a lead acid cell, or a magnesium ion cell.

In certain embodiments as otherwise described herein, the battery pack is a component of an electric vehicle. In some embodiments, the electric vehicle is an electric only vehicle or a hybrid electric vehicle. In other embodiments, the battery pack is part of a stationary energy storage solution, for example, that operates in cooperation with a local renewable energy source (such as a solar panel or wind turbine).

Another aspect of the present disclosure provides a thermal management circuit comprising a fluid path extending around and/or through an electrical component, a heat exchanger, a pump, at least one conduit connecting the fluid path, the heat exchanger and the pump, and a thermal management fluid according to any of the embodiments described above, wherein the thermal management fluid is disposed in the fluid path, the heat exchanger, the pump and the connecting conduit. For example, the thermal management circuit 100 shown in fig. 1 includes a fluid path 122 extending around an electrical component 140. The thermal management fluid 120 flows through a path 122, and the path 122 absorbs thermal energy from the electronic component 140. The thermal management fluid 120 flows from the fluid path 122 through the first conduit 130 to the heat exchanger 160. The thermal energy accumulated in the thermal management fluid 120 has been removed from the fluid in the heat exchanger 160 before the fluid flows through the second conduit 132 to the pump 170. After the pump 170, the thermal management fluid 120 passes through the third conduit 134, returning it to the fluid path 122 surrounding the electrical component 140. The circuit 100 shown in fig. 1 is a schematic diagram of a simple embodiment employing the described thermal management fluid. In other embodiments, the thermal management circuit includes additional elements, such as any combination of valves, pumps, heat exchangers, reservoirs, and tubing.

In certain embodiments as further described herein, the fluid path is defined by a housing surrounding the electrical component. For example, the housing 150 in fig. 1 surrounds the electrical component 140 and provides a cavity for the thermal management fluid 120. The electrical component 140 is held in the housing at a distance from the walls of the housing 150, which allows a path for the thermal management fluid 120 to be formed between the housing 150 and the electrical component 140. While the housing 150 has a closed shape with a specific orifice 152 that provides access to the thermal management fluid 120, in other embodiments, the top of the housing is open and the thermal management fluid is held in the housing by gravity.

In certain embodiments as further described herein, the fluid path is configured to position the thermal management fluid in sufficient thermal communication with the electrical component so as to absorb thermal energy generated by the electrical component. For example, in the thermal management circuit 100, the fluid path 122 extends around the electrical component 140 and is in direct contact with a surface of the electrical component 140. Further, in the thermal management circuit 200, the fluid path 222 passes through a conduit 246, the conduit 246 extending adjacent to an element of the electrical component 240. In both cases, the fluid path places the thermal management fluid in proximity to the electrical component so that the thermal management fluid readily absorbs thermal energy from the component.

In certain embodiments as further described herein, the heat exchanger is configured to remove heat from the thermal management fluid. For example, in the thermal management circuit 100, after the thermal management fluid 120 is pumped out of the housing 150, it passes to the heat exchanger 160 where thermal energy is transferred to a cooler fluid, such as ambient air or a cooling liquid.

In certain embodiments as otherwise described herein, the thermal management circuit comprises a battery pack according to any of the embodiments described above. For example, the thermal management circuit 200 includes a battery pack 210.

It will be apparent to those skilled in the art that various modifications and variations can be made in the processes and apparatus described herein without departing from the scope of the disclosure. It is therefore intended that the present disclosure cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Certain aspects of the disclosure are now further explained via the following non-limiting examples.

Examples of the invention

Example 1

The emulsions of the present disclosure are prepared by using the above-mentioned method. In particular, 53.9wt% paraffin wax having a melting point of 64 ℃ (Sasolwax available from Sasol), 6.9wt% emulsifier (WaxEmulsifier 2106 available from Clariant) and 6.9wt% glycerol were combined and emulsified in 32.3wt% water. After emulsification, the resulting micelles were analyzed using a beckmann coulter laser diffraction PS analyzer (LS 13320). The average particle size of the micelles in the emulsion was determined to be 0.510 μm, the median particle size 0.505 μm and the mode particle size 0.520 μm, with less than 10% of the particles having an average diameter of less than 0.415 μm or greater than 0.617 μm.

FIG. 3 shows the variation of the specific heat capacity of the obtained emulsion from-80 ℃ to +80 ℃; the data of fig. 3 is also presented in table 1 below. The peak heat capacity of about 12J/gK is due to ice generated by the melting of the continuous aqueous phase at-8.4 deg.C (note that the melting point of the solution is below 0 deg.C due to the presence of glycerol). For reference, the specific heat capacity of a fluid containing only water or 50:50 water/glycol was 4.18J/gK or 3.41J/gK, respectively. Thus, the emulsion of example 1 greatly increased the heat capacity of the coolant fluid. The second peak of the heat capacity is at the melting point of the wax.

TABLE 1

Operation of	Start (. degree.C.)	Area (J/g)	Start (. degree.C.)	Area (J/g)
					1	-8.22	79.7	51.86	103.4
2	-8.61	73.44
					3	-8.41	79.02	51.86	107.1
Mean value	-8.4	77.4	51.9	105.3
					SD	0.2	3.4	0.0	2.6

The inventors have determined that different paraffins may be selected based on their melting points. For example, paraffin waxes having melting points most relevant to the end application may be used, such as battery charging. It is also possible to provide an emulsion comprising various phase change materials, each phase change material having a different melting point and/or mass, such that the solid phase change material enters the liquid phase over a range of temperatures. This results in an emulsion that can provide a constant or varying cooling effect as desired.

It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. All publications, patents, and patent applications cited herein are hereby incorporated by reference for all purposes.

Various embodiments of the present disclosure include, but are not limited to:

1. an emulsion, comprising:

an aqueous carrier fluid; and

a micelle dispersion within an aqueous carrier fluid, wherein each micelle comprises a solid hydrophobic core particle comprising a phase change material and one or more emulsifiers forming a micelle shell around the solid hydrophobic core particle, wherein the micelles have an average particle size diameter in the range of about 0.1 μm to about 1.5 μm.

2. The emulsion of example 1, wherein the micelle size distribution d10 is not less than 50% of d50, and d90 is not greater than 150% of d50, or d10 is not less than 60% of d50, and d90 is not greater than 140% of d50, or d10 is not less than 70% of d50, or d90 is not greater than 130% of d50, or d10 is not less than 75% of d50, or d90 is not greater than 125% of d50, or d10 is not less than 80% of d50, or d90 is not greater than 120% of d 50.

3. The emulsion of embodiment 2 wherein d50 is in the range of 0.1 μm to 1.5 μm; for example, 0.1 μm to 1.2 μm, or 0.1 μm to 1.0 μm, or 0.1 μm to 0.5 μm, or 0.1 μm to 0.4 μm, or 0.2 μm to 1 μm, or 0.2 μm to 0.8 μm, or 0.2 μm to 0.6 μm, or 0.2 μm to 0.5 μm, or 0.2 μm to 0.4 μm, or 0.4 μm to 1 μm, or 0.4 μm to 0.8 μm, or 0.4 μm to 0.6 μm, or 0.4 μm to 0.5 μm, or 0.3 μm to 0.5 μm, or 0.35 μm to 0.45 μm.

4. The emulsion of embodiment 1 or 2, wherein the micelles have an average diameter in the range of 0.1 μm to 1 μm; for example, from about 0.1 μm to about 0.8 μm, or from about 0.1 μm to about 0.6 μm, or from about 0.1 μm to about 0.5 μm, or from about 0.1 μm to about 0.4 μm, or from about 0.2 μm to about 1 μm, or from about 0.2 μm to about 0.8 μm, or from about 0.2 μm to about 0.6 μm, or from about 0.2 μm to about 0.5 μm, or from about 0.2 μm to about 0.4 μm, or from about 0.4 μm to about 1 μm, or from about 0.4 μm to about 0.8 μm, or from about 0.4 μm to about 0.6 μm, or from about 0.4 μm to about 0.5 μm, or from about 0.3 μm to about 0.5 μm, or from about 0.35 μm to about 0.45 μm.

5. The emulsion of any of embodiments 1-4, wherein the one or more emulsifiers are substantially incorporated into the micelles, for example, wherein less than 5wt% or less than 2wt% or less than 1wt% or less than 0.1wt% or less than 0.01wt% or even less than 0.001wt% of the one or more emulsifiers are present in the aqueous solution in an unbound state, based on the total weight of the emulsion.

6. The emulsion of any of embodiments 1-5, wherein the phase change material is a waxy material.

7. The emulsion of any of embodiments 1-5, wherein the phase change material is a paraffin wax.

8. The emulsion of any of embodiments 1-5, wherein the phase change material is 1-cyclohexyloctadecane, 4-heptanedione, quinone, benzamide, or a mixture thereof.

9. The emulsion of any of embodiments 1-8, wherein the phase change material has a melting point of at least 30 ℃; for example, at least 50 ℃, or at least 70 ℃, or in the range of 30 ℃ to 100 ℃.

10. The emulsion of any of embodiments 1-9, wherein the micelle comprises a phase change material.

11. The emulsion of any of embodiments 1-9, wherein the micelles comprise a first set of micelles having solid hydrophobic core particles comprising a first phase change material, and a second set of micelles having solid hydrophobic core particles comprising a second phase change material different from the first phase change material.

12. The emulsion of embodiment 11 wherein the first phase change material and the second phase change material have substantially the same melting points (e.g., no more than 5 ℃ difference in melting points, or no more than 2 ℃ difference in melting points, or no more than 1 ℃ difference in melting points).

13. The emulsion of embodiment 11 wherein the first phase change material and the second phase change material have different melting points (e.g., at least 10 ℃ difference in melting points, or at least 20 ℃ difference in melting points, or at least 50 ℃ difference in melting points).

14. The emulsion of any of embodiments 1-13, wherein the phase change material is present in the composition in an amount of about 1wt% to about 70wt%, for example, about 1wt% to about 50wt%, or about 1wt% to about 30wt%, or about 1wt% to about 15wt%, or about 1wt% to about 10wt%, or about 1wt% to about 5wt%, or about 2wt% to about 70wt%, or about 2wt% to about 50wt%, or about 2wt% to about 30wt%, or about 2wt% to about 15wt%, or about 2wt% to about 10wt%, or about 5wt% to about 70wt%, or about 5wt% to about 50wt%, or about 5wt% to about 30wt%, or about 5wt% to about 15wt%, or about 10wt% to about 70wt%, or about 10wt% to about 50wt%, or about 10wt% to about 30wt%, or about 20wt% to about 70wt%, or about 20wt% to about 50wt%, or from about 40wt% to about 70 wt%.

15. The emulsion of any of embodiments 1-14, wherein the one or more emulsifiers are selected from the group consisting of molecules having a hydrocarbyl-aryl-polyether based structure.

16. The emulsion of any of embodiments 1-15, wherein the one or more emulsifiers are present in an amount of about 1wt% to about 10wt%, for example, about 1wt% to about 8wt%, or about 1wt% to about 6wt%, or about 1wt% to about 5wt%, or about 2wt% to about 10wt%, or about 2wt% to about 8wt%, or about 2wt% to about 6wt%, or about 2wt% to about 5wt%, or about 3wt% to about 10wt%, or about 3wt% to about 8wt%, or about 3wt% to about 6wt%, or about 3wt% to about 5wt%, or about 5wt% to about 10wt%, or about 5wt% to about 8wt%, or about 5wt% to about 6wt%, based on the total weight of the emulsion.

17. The emulsion of any of examples 1-16, having a heat capacity in a range of from about 10J/gK to about 35J/gK.

18. The emulsion of any of embodiments 1-17, having a thermal conductivity in a range from about 0.05W/mK to about 1W/mK.

19. The emulsion of any of examples 1-18, having a kinematic viscosity of about 3 to about 40 cSt.

20. A method of making an emulsion according to any one of embodiments 1-19, the method comprising:

obtaining a first fluid comprising one or more emulsifiers dissolved in an aqueous carrier fluid;

Obtaining a second fluid comprising one or more phase change materials;

contacting the first fluid with the second fluid under shear forces to produce an intermediate fluid; and

recovering the emulsion from the intermediate fluid.

21. The method of embodiment 20, wherein contacting the first fluid and the second fluid comprises stirring at a rotational speed in a range of about 1200 to about 1600 rpm.

22. The method of embodiment 21 or 22, further comprising contacting the intermediate fluid with a third fluid under laminar flow prior to recovering the emulsion.

23. A thermal management fluid prepared by combining the emulsion of any of examples 1-19 with an aqueous fluid, or comprising the emulsion of any of examples 1-19.

24. The thermal management fluid of embodiment 23, wherein the emulsion is used in an amount of about 1wt% to about 50wt%, for example, about 5wt% to about 40wt%, or about 5wt% to about 20wt%, or about 20wt% to about 50wt%, based on the total weight of the thermal management fluid.

25. A method, the method comprising:

passing the emulsions of examples 1-19 or the thermal management fluids of examples 23 or 24 over a surface; and

absorbing thermal energy from the thermal management fluid from the surface.

26. The method of embodiment 25, further comprising generating thermal energy by operating an electrical component.

27. The method of embodiment 25 or embodiment 26, wherein the electrical component comprises a battery, a capacitor, a fuel cell, a motor, an inverter, a cable, or a computer.

28. The method of embodiment 26 or embodiment 27, wherein the surface is a surface of an electrical component.

29. The method according to any of embodiments 25-27, wherein the surface is an interior surface of a catheter.

30. The method of embodiment 29, wherein the conduit passes through a housing surrounding the electrical component.

31. A battery pack, comprising:

a housing;

one or more electrochemical cells disposed in the housing;

a fluid path extending through the housing and in sufficient thermal communication with the one or more electrochemical cells; and

the emulsion of examples 1-19 or the thermal management fluid of examples 23 or 24 disposed in the fluid path.

32. The battery of embodiment 31, wherein the fluid path is at least partially defined by a cavity of the housing.

33. The battery pack of embodiment 31 or embodiment 32, wherein the fluid path is at least partially defined by at least one conduit disposed in the housing.

34. The battery of any of embodiments 31-33, wherein the electrochemical cell is a lithium ion electrochemical cell.

35. The battery pack according to any one of embodiments 31-34, wherein the battery pack is a component of an electric vehicle.

36. The battery pack of any of embodiments 31-34, wherein the electric vehicle is an all-electric vehicle or a hybrid electric vehicle.

37. A thermal management circuit, the thermal management circuit comprising:

a fluid path extending around and/or through the electrical component;

a heat exchanger;

a pump;

at least one conduit connecting the fluid path, the heat exchanger, and the pump; and

the emulsion of examples 1-19 or the thermal management fluid of examples 23 or 24, wherein the thermal management fluid is disposed in the fluid path, the heat exchanger, the pump, and the connecting tubing.

38. The thermal management circuit of embodiment 37, wherein the fluid path is defined by a housing surrounding the electrical component.

39. The thermal management circuit of embodiment 37 or embodiment 38, wherein the fluid path is configured to absorb thermal energy generated by an electrical component in the thermal management fluid.

40. The thermal management circuit according to any of embodiments 37-39, wherein the heat exchanger is configured to dissipate heat from the thermal management fluid.

41. The thermal management circuit according to any of embodiments 37-40, wherein the electrical component is a battery comprising a plurality of electrochemical cells, and

Wherein the fluid path passes between at least two of the electrochemical cells.

Claims (16)

1. An emulsion, comprising:

an aqueous carrier fluid; and

a micelle dispersion within the aqueous carrier fluid, wherein each micelle comprises a solid hydrophobic core particle comprising a phase change material and one or more emulsifiers forming a micelle shell around the solid hydrophobic core particle, wherein the micelles have an average particle size diameter in the range of about 0.1 μ ι η to about 1.5 μ ι η.

2. The emulsion of claim 1, wherein the micelles have an average diameter in the range of 0.1 μ ι η to 1 μ ι η; for example, from about 0.1 μm to about 0.8 μm, or from about 0.1 μm to about 0.6 μm, or from about 0.1 μm to about 0.5 μm, or from about 0.1 μm to about 0.4 μm, or from about 0.2 μm to about 1 μm, or from about 0.2 μm to about 0.8 μm, or from about 0.2 μm to about 0.6 μm, or from about 0.2 μm to about 0.5 μm, or from about 0.2 μm to about 0.4 μm, or from about 0.4 μm to about 1 μm, or from about 0.4 μm to about 0.8 μm, from about 0.4 μm to about 0.6 μm, or from about 0.4 μm to about 0.5 μm, or from about 0.3 μm to about 0.5 μm, or from about 0.35 μm to about 0.45 μm.

3. The emulsifier according to claim 1 or 2, wherein the one or more emulsifiers are substantially incorporated into the micelles, e.g. wherein less than 5wt% or less than 2wt% or less than 1wt% or less than 0.1wt% or less than 0.01wt% or even less than 0.001wt% of the one or more emulsifiers are present in an unbound state in an aqueous solution, based on the total weight of the emulsion.

4. An emulsion according to any one of claims 1 to 3, characterized in that the phase change material is a waxy material.

5. An emulsion according to any one of claims 1 to 3, characterized in that the phase change material is paraffin.

6. An emulsion according to any of claims 1 to 3, wherein the phase change material is 1-cyclohexyloctadecane, 4-heptanedione, quinone, benzamide, or a mixture thereof.

7. The emulsion of any one of claims 1-6, wherein the phase change material has a melting point of at least 30 ℃; for example, at least 50 ℃, or at least 70 ℃, or in the range of 30 ℃ to 100 ℃.

8. An emulsion according to any of claims 1 to 7, wherein the micelles comprise a phase change material.

9. An emulsion according to any of claims 1 to 7, wherein the micelles comprise a first set of micelles having solid hydrophobic core particles comprising a first phase change material, and a second set of micelles having solid hydrophobic core particles comprising a second phase change material different from the first phase change material.

10. The emulsion of any one of claims 1-9, wherein the phase change material is present in the composition in an amount of about 1wt% to about 70wt%, for example, about 1wt% to about 50wt%, or about 1wt% to about 30wt%, or about 1wt% to about 15wt%, or about 1wt% to about 10wt%, or about 1wt% to about 5wt%, or about 2wt% to about 70wt%, or about 2wt% to about 50wt%, or about 2wt% to about 30wt%, or about 2wt% to about 15wt%, or about 2wt% to about 10wt%, or about 5wt% to about 70wt%, or about 5wt% to about 50wt%, or about 5wt% to about 30wt%, or about 5wt% to about 15wt%, or about 10wt% to about 70wt%, or about 10wt% to about 50wt%, or about 10wt% to about 30wt%, or from about 20wt% to about 70wt%, or from about 20wt% to about 50wt%, or from about 40wt% to about 70 wt%.

11. An emulsion according to any of claims 1 to 10, characterized in that the one or more emulsifiers are selected from the group consisting of molecules having a hydrocarbyl-aryl-polyether based structure.

12. The emulsion of any one of claims 1-11, wherein the emulsion has a heat capacity in a range from about 10J/gK to about 35J/gK.

13. The emulsion of any one of claims 1-11, wherein the emulsion has a thermal conductivity in the range of about 0.05W/mK to about 1W/mK.

14. The emulsion of any one of claims 1-13, wherein the emulsion has a kinematic viscosity of about 3 to about 40 cSt.

15. A thermal management fluid prepared by combining the emulsion of any one of claims 1-14 with an aqueous fluid, or comprising the emulsion of any one of claims 1-14.

16. A battery pack, comprising:

a housing;

one or more electrochemical cells disposed in the housing;

a fluid path extending through the housing and in sufficient thermal communication with the one or more electrochemical cells; and

The emulsion of claims 1-14 or the thermal management fluid of claim 15 disposed in the fluid path.

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